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Physiological Response of Corynebacterium glutamicum to Indole

The aromatic heterocyclic compound indole is widely spread in nature. Due to its floral odor indole finds application in dairy, flavor, and fragrance products. Indole is an inter- and intracellular signaling molecule influencing cell division, sporulation, or virulence in some bacteria that synthesi...

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Autores principales: Walter, Tatjana, Veldmann, Kareen H., Götker, Susanne, Busche, Tobias, Rückert, Christian, Kashkooli, Arman Beyraghdar, Paulus, Jannik, Cankar, Katarina, Wendisch, Volker F.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
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Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7764795/
https://www.ncbi.nlm.nih.gov/pubmed/33302489
http://dx.doi.org/10.3390/microorganisms8121945
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author Walter, Tatjana
Veldmann, Kareen H.
Götker, Susanne
Busche, Tobias
Rückert, Christian
Kashkooli, Arman Beyraghdar
Paulus, Jannik
Cankar, Katarina
Wendisch, Volker F.
author_facet Walter, Tatjana
Veldmann, Kareen H.
Götker, Susanne
Busche, Tobias
Rückert, Christian
Kashkooli, Arman Beyraghdar
Paulus, Jannik
Cankar, Katarina
Wendisch, Volker F.
author_sort Walter, Tatjana
collection PubMed
description The aromatic heterocyclic compound indole is widely spread in nature. Due to its floral odor indole finds application in dairy, flavor, and fragrance products. Indole is an inter- and intracellular signaling molecule influencing cell division, sporulation, or virulence in some bacteria that synthesize it from tryptophan by tryptophanase. Corynebacterium glutamicum that is used for the industrial production of amino acids including tryptophan lacks tryptophanase. To test if indole is metabolized by C. glutamicum or has a regulatory role, the physiological response to indole by this bacterium was studied. As shown by RNAseq analysis, indole, which inhibited growth at low concentrations, increased expression of genes involved in the metabolism of iron, copper, and aromatic compounds. In part, this may be due to iron reduction as indole was shown to reduce Fe(3+) to Fe(2+) in the culture medium. Mutants with improved tolerance to indole were selected by adaptive laboratory evolution. Among the mutations identified by genome sequencing, mutations in three transcriptional regulator genes were demonstrated to be causal for increased indole tolerance. These code for the regulator of iron homeostasis DtxR, the regulator of oxidative stress response RosR, and the hitherto uncharacterized Cg3388. Gel mobility shift analysis revealed that Cg3388 binds to the intergenic region between its own gene and the iolT2-rhcM2D2 operon encoding inositol uptake system IolT2, maleylacetate reductase, and catechol 1,2-dioxygenase. Increased RNA levels of rhcM2 in a cg3388 deletion strain indicated that Cg3388 acts as repressor. Indole, hydroquinone, and 1,2,4-trihydroxybenzene may function as inducers of the iolT2-rhcM2D2 operon in vivo as they interfered with DNA binding of Cg3388 at physiological concentrations in vitro. Cg3388 was named IhtR.
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spelling pubmed-77647952020-12-27 Physiological Response of Corynebacterium glutamicum to Indole Walter, Tatjana Veldmann, Kareen H. Götker, Susanne Busche, Tobias Rückert, Christian Kashkooli, Arman Beyraghdar Paulus, Jannik Cankar, Katarina Wendisch, Volker F. Microorganisms Article The aromatic heterocyclic compound indole is widely spread in nature. Due to its floral odor indole finds application in dairy, flavor, and fragrance products. Indole is an inter- and intracellular signaling molecule influencing cell division, sporulation, or virulence in some bacteria that synthesize it from tryptophan by tryptophanase. Corynebacterium glutamicum that is used for the industrial production of amino acids including tryptophan lacks tryptophanase. To test if indole is metabolized by C. glutamicum or has a regulatory role, the physiological response to indole by this bacterium was studied. As shown by RNAseq analysis, indole, which inhibited growth at low concentrations, increased expression of genes involved in the metabolism of iron, copper, and aromatic compounds. In part, this may be due to iron reduction as indole was shown to reduce Fe(3+) to Fe(2+) in the culture medium. Mutants with improved tolerance to indole were selected by adaptive laboratory evolution. Among the mutations identified by genome sequencing, mutations in three transcriptional regulator genes were demonstrated to be causal for increased indole tolerance. These code for the regulator of iron homeostasis DtxR, the regulator of oxidative stress response RosR, and the hitherto uncharacterized Cg3388. Gel mobility shift analysis revealed that Cg3388 binds to the intergenic region between its own gene and the iolT2-rhcM2D2 operon encoding inositol uptake system IolT2, maleylacetate reductase, and catechol 1,2-dioxygenase. Increased RNA levels of rhcM2 in a cg3388 deletion strain indicated that Cg3388 acts as repressor. Indole, hydroquinone, and 1,2,4-trihydroxybenzene may function as inducers of the iolT2-rhcM2D2 operon in vivo as they interfered with DNA binding of Cg3388 at physiological concentrations in vitro. Cg3388 was named IhtR. MDPI 2020-12-08 /pmc/articles/PMC7764795/ /pubmed/33302489 http://dx.doi.org/10.3390/microorganisms8121945 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Walter, Tatjana
Veldmann, Kareen H.
Götker, Susanne
Busche, Tobias
Rückert, Christian
Kashkooli, Arman Beyraghdar
Paulus, Jannik
Cankar, Katarina
Wendisch, Volker F.
Physiological Response of Corynebacterium glutamicum to Indole
title Physiological Response of Corynebacterium glutamicum to Indole
title_full Physiological Response of Corynebacterium glutamicum to Indole
title_fullStr Physiological Response of Corynebacterium glutamicum to Indole
title_full_unstemmed Physiological Response of Corynebacterium glutamicum to Indole
title_short Physiological Response of Corynebacterium glutamicum to Indole
title_sort physiological response of corynebacterium glutamicum to indole
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7764795/
https://www.ncbi.nlm.nih.gov/pubmed/33302489
http://dx.doi.org/10.3390/microorganisms8121945
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